We have had success using pgremapper[1] for this sort of thing, in both index and data augments. 1. Set nobackfill, norebalance 2. Add OSDs 3. pgremapper cancel-backfill 4. Unset flags 5. Slowly loop `pgremapper undo-upmaps` at our desired rate, or allow the balancer to do this work There's still going to be the hit from peering, especially when you change the CRUSH map (before even bringing the OSDs in), but in general peering has been very quick for us for the last few releases, and s3 has enough overhead where it's not overly noticed. We haven't done multiple OSDs per device, however, and have plenty CPU power. [1] https://github.com/digitalocean/pgremapper On 2023-08-29 17:51, Szabo, Istvan (Agoda) wrote: > Hello, > > Is there a way to somehow fine tune the rebalance even further than > basic tuning steps when adding new osds? > Today I've added some osd to the index pool and it generated many slow > ops due to OSD op latency increase + read operation latency increase = > high put get latency. > > https://ibb.co/album/9mN6GQ > > osd max backfill, max recovery, recovery ops priority are 1. > 1 nvme drive has 4 osd, each osd has around 80pg. > > The steps how I add the osds: > > 1. Set norebalance > 2. add the osds > 3. wait for peering > 4. unset rebalance > > It takes like 15-20 mins to became normal without interrupting the > rebalance the user traffic. > > Thank you, > Istvan > > ________________________________ > This message is confidential and is for the sole use of the intended > recipient(s). It may also be privileged or otherwise protected by > copyright or other legal rules. If you have received it by mistake > please let us know by reply email and delete it from your system. It is > prohibited to copy this message or disclose its content to anyone. Any > confidentiality or privilege is not waived or lost by any mistaken > delivery or unauthorized disclosure of the message. All messages sent > to and from Agoda may be monitored to ensure compliance with company > policies, to protect the company's interests and to remove potential > malware. Electronic messages may be intercepted, amended, lost or > deleted, or contain viruses. > _______________________________________________ > ceph-users mailing list -- ceph-users(a)ceph.io > To unsubscribe send an email to ceph-users-leave(a)ceph.io

The "osdmaptool" can be used. like this: $ ceph osd getmap -o om $ osdmaptool om --upmap out.txt --upmap-pool xxx --upmap-deviation 5 --upmap-max 10 $ cat out.txt $ source out.txt